Sending XML with CFHTTP

I have some code that works perfectly well with one customer, but with another it's a total fail. They are telling me that the content type is not being sent.

The goal is to send a XML data to them over SSL/Port 8443

Am I missing something here that some servers react badly to?

<cfparam name="form_timeout" default="5">

<cfparam name="form_port" default="8443">

<cfset objXml = createObject("component","xml2Struct")>

<!--- Request XML--->

<cfxml variable="xmlRequest">

<?xml version="1.0" encoding="UTF-8"?>

<request>

<header>

<signature>BHNUMS</signature>

<details>

<productCategoryCode>01</productCategoryCode>

<specVersion>43</specVersion>

</details>

</header>

<transaction>

<primaryAccountNumber>9877890000000000001</primaryAccountNumber>

<processingCode>615400</processingCode>

<transactionAmount>000000000000</transactionAmount>

<transmissionDateTime>140223183057</transmissionDateTime>

<systemTraceAuditNumber>385224</systemTraceAuditNumber>

<localTransactionTime>103057</localTransactionTime>

<localTransactionDate>140223</localTransactionDate>

<merchantCategoryCode>5411</merchantCategoryCode>

<pointOfServiceEntryMode>011</pointOfServiceEntryMode>

<acquiringInstitutionIdentifier>60300000063</acquiringInstitutionIdentifier>

<retrievalReferenceNumber>000007385224</retrievalReferenceNumber>

<merchantTerminalId>26065     001   </merchantTerminalId>

<merchantIdentifier>60300000063    </merchantIdentifier>

<merchantLocation>Simulation</merchantLocation>

<transactionCurrencyCode>840</transactionCurrencyCode>

<additionalTxnFields>

<productId>07675019009</productId>

<redemptionPin>#form_redemptioncode#</redemptionPin>

</additionalTxnFields>

</transaction>

</request>

</cfxml>

<!---Make a test request --->

<cfhttp url="HTTPS URL OF CUSTOMER HERE" method="post" port="#form_port#" timeout="#form_timeout#">

    <cfhttpparam type="header" name="Accept" value="application/xml" />

    <cfhttpparam type="header" name="Accept-Language" value="en-us,en" />

    <cfhttpparam type="header" name="Accept-Charset" value="utf-8" />

    <cfhttpparam type="header" name="Keep-Alive" value="115" />

    <cfhttpparam type="header" name="Connection" value="keep-alive" />

    <cfhttpparam type="body" value="#xmlRequest#" />

</cfhttp>

<CFOUTPUT>#cfhttp.statuscode#</CFOUTPUT>